Perth located on 118° East Longitude will be celebrating New Year event on 1st of January 2017 at 6:00 AM. At that time, what would be the time at Los Angeles located on 110° West Longitude ?
9:12 PM of 1<sup>st</sup> January 2017
2:48 PM of 31<sup>st</sup> December 2016
11:40 PM of 31<sup>st</sup> December 2016
5:28 AM of 1<sup>st</sup> January 2017
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CAPF – 2016
– Longitude of Los Angeles = 110° West.
– The total difference in longitude = 118° (East) + 110° (West) = 228°.
– The Earth rotates 360° in 24 hours.
– The time difference for 1° longitude = 24 hours / 360° = 1/15 hours = 4 minutes.
– The total time difference between Perth and Los Angeles = 228° * 4 minutes/° = 912 minutes.
– Convert minutes to hours: 912 minutes / 60 minutes/hour = 15 hours and 12 minutes (912 = 15 * 60 + 12).
– Perth is located in the East, so its time is ahead of Los Angeles, which is in the West.
– Time at Los Angeles = Time at Perth – Time difference.
– Time at Perth = 6:00 AM on 1st January 2017.
– Subtract 15 hours 12 minutes from 6:00 AM, 1st January 2017.
– Subtracting 6 hours from 6:00 AM Jan 1st gives 0:00 AM (midnight) on Jan 1st.
– We need to subtract another 15h 12m – 6h = 9h 12m.
– Subtracting 9 hours from 0:00 AM Jan 1st gives 15:00 (3:00 PM) on 31st December 2016.
– Subtracting the final 12 minutes from 3:00 PM Dec 31st gives 14:48 PM (2:48 PM) on 31st December 2016.